In April 2016, Andra sent ASN the safety options file (DOS) for the Cigeo radioactive waste deep disposal project. Submission of a DOS means that the project becomes part of a process governed by the regulations concerning basic nuclear installations (BNI), more specifically by article 6 of the decree of 2November 2007.

ASN examined this file. In this respect, it requested an expert assessment from its technical support organisation, IRSN. It had this file assessed by the Advisory Committees of experts reporting to it. It also submitted it for review by experts from foreign safety regulators, coordinated by the IAEA.

Following this technical examination phase, ASN consulted the public about its draft opinion from 1 August to 15 September 2017. After analysis of the contributions received, ASN issued its opinion on 11 January 2018.

The management solution adopted in France for high level, or intermediate level long-lived radioactive waste (HLW/ILW-LL) is deep geological disposal. The Cigeo project aims to implement this principle as enshrined in law.

ASN considers that the Cigeo project has on the whole achieved sufficient technical maturity at the safety options file stage. It also considers that the safety options file is documented and substantiated and constitutes a significant step forward with respect to the previous files submitted to ASN for its opinion.

However, certain subjects of the safety options file need to be supplemented in view of the creation authorisation application that Andra intends to submit in 2019. The main supplements requested concern the justification of the disposal architecture, the design and sizing of the installation to withstand natural hazards, the monitoring of the facility and the management of post-accident situations.

ASN also expressed a reservation with regard to bituminous waste. It considers that "particular attention should be given to research on neutralising the chemical reactivity of the packages of bituminous waste. At the same time, studies to modify the design to preclude the risk of runaway exothermal reactions should be carried out. In any case, characterisation of these packages of bituminous waste by their producers as rapidly as possible is an essential precondition”.

ASN is also sending Andra a letter "specifying the satisfactory safety options and the additional studies and demonstrations necessary for the creation authorisation application”. The requests in this letter take account of the public’s suggestions and comments concerning the draft opinion.

The French Nuclear Safety Authority is tasked, on behalf of the State, with regulating nuclear safety and radiation protection in order to protect workers, patients, the public and the environment from the risks involved in nuclear activities in France. It also contributes to informing the citizens.